What's the chance Austro will develop an aluminum block and not simply manufacture the boat anchor cast iron blocks of the MB OM640? And how "competitive" will the price be when they are making a few hundred engines a year versus the tens of thousands manufactured by MB?

The original 1.7 litre Mercedes engine used by Thielert had an aluminium block. Mercedes superseded it with a 2 litre cast iron block, and Thielert chose to adapt it with their own aluminium block so that it could be substituted with no change to W&B. This expense, for the benefit of Diamond, helped to bankrupt them.

Austro just took the Mercedes engine as is, and Diamond beefed up the airframe to cope with the extra 50kg, so had to go through the recertification process.

Mercedes have now superseded that engine with another with an aluminium block. Maybe Austro will have to adopt it, if they run out of supplies for their current engines, or maybe Mercedes will abandon diesel engines altogether, now that the truth is known about their particulate emissions.

Back around 2006-2009 Diamond (actually the Dries family that owned Diamond back then) invested around $50m to start Austro Engine and certify the AE300 engine. They wisely leveraged as much proven Mercedes-Benz auto engine technology as possible by purchasing a large number of OM640 car engines directly from Mercedes -- engines that Austro put into storage.

Every time they needed to build a new aircraft engine, Austro went into their "back room" to get an OM640 engine, stripped off the Mercedes accessories; added a gearbox, Bosch ECUs, and other aircraft accessories; and created an AE300 or AE330. They didn't need to take apart the OM640 engine core, including the cast-iron block.

Now with more than a thousand Austro engines flying, Austro is running out of original OM640 Mercedes car engines. Mercedes 4-cylinder car diesels are now 2+ generations newer, so Mercedes stopped producing OM640 engines many years ago.

Austro cannot change the design of the AE300/330 without very expensive re-certification of the engines (and Diamond would need to re-certify its aircraft), so it's highly unlikely that Austro would start producing a different engine based on newer-generation Mercedes engines, even if based on a lighter aluminum block.

The logical step is for Austro to start producing its own OM640 engine cores. I'm guessing they can utilize many of the same component parts suppliers that originally supplied Mercedes-Benz, as well as outsourcing core engine assembly.

If I understood correctly when in Weiner Neustadt recently, Austro now holds the licence from MB to manufacture the subject engines. As quite rightly pointed out, to deviate would require recertification and all that this entails. There was no concern shown with regard to this development.

They re-certified to put the NG on the DA42 in the first place, it seems short-sighted not to use the opportunity to move up in engine technology. But I'm not writing the checks and I don't know what that effort cost them.

They re-certified to put the NG on the DA42 in the first place, it seems short-sighted not to use the opportunity to move up in engine technology. But I'm not writing the checks and I don't know what that effort cost them.

Diamond didn't have a choice back in 2008 with Thielert going bankrupt; it was temporarily stuck with DA42 airframes with no engines until the DA42NG with Austro engines was certified in 2009. So Diamond HAD to spend the money for AE300 certification.

Diamond today is in a completely different (i.e., MUCH better) position. But the economics of spending large sums of money to certify an all-new aviation engine that will only ship a few hundred per year are still unfavorable. That's why Lycoming and Continental are still building antiquated piston engines with tractor magnetos -- they can't afford to certify newer engines with so few engines being produced.

Using old engine is not unusual in aviation look at Lycosaurus world. The problem is when you don’t have steady production stream of new engines. Looking at Diamond’s strategy for DA42-VI and DA62, I doubt that they don’t have clear plan on producing Austro engines. Or maybe they are considering return to CD

One of the reported differences between the cast iron core/block and the aluminum core/block is that the former can be overhauled and the latter cannot. This is not an issue for typical passenger vehicle automotive applications. Appreciate the history and perspectives of the previous posts on this thread. Thanks!